Contamination monitors and radiation dose meters are common for use in industries in which the presence of and exposure to low levels of radioactive materials is a hazard. For example, in drilling operations, the formation of radioactive scales on the platform may occur and it is usual for the platform to be checked periodically to detect such scales and other materials which may pose a hazard to workers. These environments may also present other hazards such as the risk of fire or explosion due to the possible presence of combustible gas or liquids. In such environments, such as those encountered in oil and gas exploration, it is necessary to use intrinsically safe equipment in order to eliminate the risk of igniting combustible gases through sparking.